Patentable/Patents/US-11081768
US-11081768

Fabricating an RF filter on a semiconductor package using selective seeding

PublishedAugust 3, 2021
Assigneenot available in USPTO data we have
Inventorsnot available in USPTO data we have
Technical Abstract

A filter structure comprises a first dielectric buildup film. A second dielectric buildup film is over the first dielectric buildup film, the second dielectric buildup film including a metallization catalyst. A trench is in the second dielectric buildup film. A metal is selectively plated to sidewalls of the trench based at least in part on the metallization catalyst. A low-loss buildup film is over the metal that substantially fills the trench.

Patent Claims
21 claims

Legal claims defining the scope of protection, as filed with the USPTO.

1

1. A filter structure, comprising: a first dielectric buildup film; a second dielectric buildup film over the first dielectric buildup film, the second dielectric buildup film comprising a dielectric material that contains a metallization catalyst, wherein the dielectric material comprises one of an epoxy-polymer blend dielectric material, silicon dioxide and silicon nitride, and a low-k dielectric; a trench in the second dielectric buildup film; a metal selectively plated to sidewalls of the trench based at least in part on the metallization catalyst; and a low-loss buildup film over the metal that substantially fills the trench.

2

2. The filter structure of claim 1 , wherein the metallization catalyst comprises one of: palladium (Pd), aluminum (Al), ruthenium (Ru), titanium (Ti), gold (Au), copper (Cu), silver (Ag), and cobalt (Co).

3

3. The filter structure of claim 1 , wherein the filter structure comprises one of: an RF filter, an RF amplifier, a waveguide, and a resonator.

4

4. The filter structure of claim 1 , wherein the low-loss buildup film comprises a buildup polymer with a silica filler.

5

5. The filter structure of claim 1 , wherein the trench further comprises: a plurality of fins located along opposing sidewalls of the trench, wherein the metal is plated to sidewalls of the fins to form metal plated cavities between laterally adjacent ones of the fins.

6

6. The filter structure of claim 1 , wherein a plurality of fins are recessed within the trench such that the plurality of fins have a height below that of sidewalls of the trench.

7

7. The filter structure of claim 1 , wherein the filter structure is approximately 2000-4000 μm in length.

8

8. The filter structure of claim 1 , wherein the filter structure is approximately 30-100 μm in height.

9

9. The filter structure of claim 1 , wherein the filter structure is approximately 100-500 μm in width.

10

10. The filter structure of claim 1 , wherein the metallization catalyst in the second dielectric buildup film comprises palladium (Pd), and wherein the second dielectric buildup film further includes an inactive region and an active region, where the inactive region contains ionic Pd (n+), while the active region contains both contains ionic Pd (n+) and Pd in oxidation state ( 0 ).

11

11. A filter structure, comprising: a first dielectric buildup film; a second dielectric buildup film over the first dielectric buildup film, the second dielectric buildup film including a metallization catalyst; a trench in the second dielectric buildup film, wherein the trench further comprises a plurality of fins located along opposing sidewalls of the trench, wherein the metal is plated to sidewalls of the fins to form metal plated cavities between laterally adjacent ones of the fins; a metal selectively plated to sidewalls of the trench based at least in part on the metallization catalyst; and a low-loss buildup film over the metal that substantially fills the trench.

12

12. An RF filter structure, comprising: a first dielectric buildup film; a metal pad on the first dielectric buildup film; a second dielectric buildup film laminated to the metal pad, the second dielectric buildup film including a metallization catalyst; a trench in the second dielectric buildup film down to the metal pad, wherein the trench includes a plurality of laterally spaced fins on two opposing trench sidewalls, where pairs of the fins on the opposing trench sidewalls have variably sized gaps therebetween; a metal selectively plated to the trench sidewalls and sidewalls of the fins based at least in part on activation of the metallization catalyst at an interface between the second dielectric buildup film and the sidewalls of the trench and fins; and a low-loss buildup film over the metal that substantially fills the trench.

13

13. The RF filter structure of claim 12 , wherein the metallization catalyst comprises one of: palladium (Pd), aluminum (Al), ruthenium (Ru), titanium (Ti), gold (Au), copper (Cu), silver (Ag), and cobalt (Co).

14

14. The RF filter structure of claim 12 , wherein the low-loss buildup film comprises a buildup polymer with a silica filler.

15

15. The RF filter structure of claim 12 , wherein the metal is plated to sidewalls of the trench and the plurality of laterally spaced fins to form metal plated cavities between laterally adjacent ones of the plurality of laterally spaced fins.

16

16. The RF filter structure of claim 12 , wherein the fins are recessed within the trench such that the fins have a height below that of the trench sidewalls.

17

17. The RF filter structure of claim 12 , wherein the RF filter structure is approximately 2000-4000 μm in length.

18

18. The RF filter structure of claim 12 , wherein the RF filter structure is approximately 30-100 μm in height.

19

19. The RF filter structure of claim 12 , wherein the RF filter structure is approximately 100-500 μm in width.

20

20. The RF filter structure of claim 12 , wherein the metallization catalyst in the second dielectric buildup film comprises palladium (Pd), and wherein the second dielectric buildup film further includes an inactive region and an active region, where the inactive region contains ionic Pd (n+), while the active region contains both contains ionic Pd (n+) and Pd in oxidation state ( 0 ).

21

21. A filter structure, comprising: a first dielectric buildup film; a second dielectric buildup film over the first dielectric buildup film, the second dielectric buildup film including a metallization catalyst; a trench in the second dielectric buildup film; a plurality of fins recessed within the trench such that the plurality of fins have a height below that of sidewalls of the trench; a metal selectively plated to sidewalls of the trench based at least in part on the metallization catalyst; and a low-loss buildup film over the metal that substantially fills the trench.

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Patent Metadata

Filing Date

May 24, 2019

Publication Date

August 3, 2021

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Cite as: Patentable. “Fabricating an RF filter on a semiconductor package using selective seeding” (US-11081768). https://patentable.app/patents/US-11081768

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